1. Field of Invention
The present invention relates to a substrate of a display device, and more particularly, to a substrate of a display device for packaging a driving integrated circuit (IC).
2. Description of Related Art
With the progression of the information age, flat panel display (FPD) devices having light weight, thin profile, and low power consumption characteristics are being developed and commonly used as substitutes for cathode ray tube (CRT) devices. Generally, display devices are classified as emissive display devices and non-emissive display devices according to their light emitting capabilities. The emissive display devices display images by taking advantage of their ability to emit light while the non-emissive display devices require a light source because they cannot emit light by themselves. For example, plasma display panel (PDP) devices, field emission display (FED) devices, and electroluminescent display (ELD) devices are common examples of emissive display devices. Liquid crystal display (LCD) devices, on the other hand, are categorized as non-emissive display devices. Even though LCD devices are non-emissive display devices, they are commonly used in notebook and desktop computers because of their high resolution, high quality color-displaying capabilities.
An LCD module of the LCD device includes an LCD panel for displaying images, a backlight unit for supplying light to the LCD panel, and a driving unit for driving the LCD panel. The driving unit is generally positioned along a periphery of the LCD panel. The LCD panel includes two substrates facing and spaced apart from each other with a liquid crystal material interposed therebetween. A plurality of matrix-type pixels connected to a plurality of thin film transistors that supply signals to the pixels are formed on one of the two substrates.
The driving unit includes a printed circuit board (PCB) on which a plurality of elements generating various control signals and data signals are packaged. A driving integrated circuit (IC) connected to the PCB on the LCD panel applies signals to the signal lines of the LCD panel through the PCB. The LCD panels are generally manufactured using three types of techniques: (1) chip-on-glass (COG), (2) tape carrier package, and (3) chip-on-film. In particular, the COG type LCD panels commonly include the driving ICs directly packaged on the substrate of the LCD panel.
FIG. 1 is a schematic plan view showing a substrate of a display device having pads for packaging a driving IC according to the related art. FIG. 2 is a schematic plan view showing a driving IC having lead patterns that connect to the substrate of FIG. 1 according to the related art.
As shown in FIG. 1, an input pad (IP) group and an output pad (OP) group are formed on a substrate 10 and are arranged within a packaging area of a driving IC 20 (illustrated as a dotted region). Specifically, the input pad group IP includes a plurality of input pads 22, and the output pad group OP includes a plurality of output pads 24. Gate lines GL formed in a display region (not shown) are connected to the output pad group OP. FIG. 2 illustrates a driving IC 20 including a set of input leads (IL) and a set of output leads (OL) to be packaged on the substrate 10.
FIG. 1 illustrates an exemplary arrangement structure of the input pad group IP and the output pad group OP on a COG type LCD panel corresponding to the input leads IL and the output leads OL of the driving IC 20. Because of varying designs used by driving IC manufacturers, the arrangement of the input pad group IP and the output pad group OP formed on the substrate 10 may or may not match the arrangement of the input leads IL and the output leads OL of the driving IC 20. Therefore, when the output leads OL of the driving IC 20 have a zigzag pattern, the pads 22 and 24 of the input pad group IP and the output pad group OP, respectively, may not properly correspond to the input and output lead patterns IL and OL of the driving IC 20. As a result, utility and reliability of the substrate 10 coupled with the driving IC 20 are reduced, leading to an increase in fabrication processes and production costs in order to manufacture new substrates to match new driving ICs having new lead patterns.